LiDAR

Abstract

A laser radar comprises: a light source, which is suitable for generating at least one line of detection light; a transmitting lens, which is arranged downstream of the optical path of the detection light generated by the light source; a beam splitter prism, which is arranged on the optical path of the transmitting lens, and which covers part of the aperture stop of the transmitting lens; any detection light transmitted through the transmitting lens partially transmits through the beam splitter prism, and partially does not transmit through the beam splitter prism; part of the detection light transmitted through the beam splitter prism and part of the detection light not transmitted through the beam splitter prism respectively form corresponding exit lights, which are reflected by obstacles to form echo lights collected by different detectors. The beam splitter prism realizes beam splitting through the principle of light refraction, which reduces the dependence of the beam splitting angle on the wavelength of light, thereby being able to improve the accuracy of the vertical angular resolution of the laser radar while increasing the number of laser lines without increasing the number of lasers.

Description

Technical Field

[0001] The present invention relates to the field of laser detection, and in particular to a laser radar. Background Art

[0002] LiDAR is a commonly used distance measurement sensor with the characteristics of long detection distance, high resolution, and low environmental interference. It is widely used in intelligent robots, drones, unmanned driving and other fields. The working principle of LiDAR is similar to that of micron-wave radar, both of which use the time it takes for light waves to travel back and forth between the radar and the target to evaluate the distance.

[0003] Early laser radars were single-line laser radars, which only had one laser and detector. Their target scanning range and angular resolution were limited, which easily resulted in the loss of detected targets. In order to make up for the shortcomings of single-line laser radars, multi-line laser radars have become an increasingly important research and commercial focus.

[0004] The number of lines of the current integrally rotating mechanical multi-line LiDAR depends entirely on the number of lasers. The number of lines and the number of lasers are equal. Increasing the number of lines of the LiDAR means an increase in the number of lasers, which will increase the cost of the LiDAR exponentially and significantly increase the energy consumption of the LiDAR.

[0005] In order to control the number of lasers to control costs and energy consumption, a spectrometer is set in the optical path of the laser radar. However, the setting of the existing spectrometer has poor controllability of the spectrometer angle, which affects the accuracy of the angular resolution of the laser radar. Summary of the invention

[0006] The problem solved by the present invention is: how to improve the splitting accuracy and controllability to improve the accuracy of the vertical angular resolution of the laser radar while setting a splitting device to increase the number of laser lines without increasing the number of lasers.

[0007] In order to solve the above problems, the present invention provides a laser radar, comprising:

[0008] A light source, wherein the light source is suitable for generating at least one line of detection light; a transmitting lens, wherein the transmitting lens is arranged downstream of the optical path of the detection light generated by the light source; a dichroic prism, wherein the dichroic prism is arranged on the optical path of the transmitting lens, and the dichroic prism covers a portion of the aperture stop of the transmitting lens; any line of detection light transmitted through the transmitting lens partially transmits through the dichroic prism, and partially does not transmit through the dichroic prism; the portion of detection light transmitted through the dichroic prism and the portion of detection light not transmitted through the dichroic prism respectively form corresponding emergent light, and the emergent light is reflected by an obstacle to form echo light collected by different detectors.

[0009] Optionally, the beam splitter prism is arranged at the position of the aperture stop of the emitting lens.

[0010] Optionally, the beam splitter prism is located between the emitting lens and the light source, or on a side of the emitting lens away from the light source, or in the middle of the emitting lens.

[0011] Optionally, the beam splitter prism is fixed by bonding or bracket.

[0012] Optionally, the beam splitter prism includes N wedge prisms, where N is an integer greater than or equal to 1.

[0013] Optionally, the angle between a perpendicular plane of the wedge angle edge line of the wedge prism and the meridian plane of the emitting lens is not equal to 90°.

[0014] Optionally, a vertical plane of the wedge angle edge line of the wedge prism is parallel to the meridian plane of the emitting lens.

[0015] Optionally, when N is greater than 1, the N wedge-shaped prisms are stacked in sequence along the optical path.

[0016] Optionally, the vertical planes of the wedge angle edges of the N wedge prisms are parallel.

[0017] Optionally, the range of the aperture stop covered by the Mth wedge-shaped prism is within the range of the aperture stop covered by the M-1th wedge-shaped prism, where M is an integer in the range of 2 to N.

[0018] Optionally, part of the detection light that has not passed through the wedge-shaped prism forms the first output light; part of the detection light that has passed through one wedge-shaped prism forms the second output light; part of the detection light that has passed through two wedge-shaped prisms forms the third output light; ...; part of the detection light that has passed through X wedge-shaped prisms forms the X+1th output light, where X is an integer in the range of 1 to N.

[0019] Optionally, the energies of the first emergent light, the second emergent light, the third emergent light, ..., and the X+1th emergent light are equal.

[0020] Optionally, the light source includes Z lasers to generate Z-line detection light; part of the detection light is transmitted through at most X wedge-shaped prisms; the laser radar also includes: a detector, which is suitable for receiving the echo light; the number of the detectors is Z×(X+1).

[0021] Optionally, the number of detectors is equal to the number of lines of emitted light.

[0022] Optionally, the beam splitter prism includes two wedge-shaped prisms, namely a first wedge-shaped prism and a second wedge-shaped prism, the wedge angles of the first wedge-shaped prism and the second wedge-shaped prism are not equal, and the range of the aperture stop covered by the first wedge-shaped prism and the second wedge-shaped prism partially overlaps.

[0023] Optionally, part of the detection light that does not pass through the wedge-shaped prism forms the first output light, part of the detection light that only passes through the first wedge-shaped prism forms the second output light, part of the detection light that only passes through the second wedge-shaped prism forms the third output light, and part of the detection light that passes through the overlapping part of the first wedge-shaped prism and the second wedge-shaped prism forms the fourth output light, and the energies of the first output light, the second output light, the third output light and the fourth output light are equal.

[0024] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0025] In the technical solution of the present invention, any detection light that transmits the emitting lens partially transmits the beam splitter prism, and partially does not transmit the beam splitter prism. Under the refraction of the beam splitter prism, the propagation direction of the portion of the detection light that transmits the beam splitter prism changes, thereby deviating from the original light path direction. Through the setting of the beam splitter prism, the portion of the detection light that transmits the beam splitter prism and the portion of the detection light that does not transmit the beam splitter prism respectively form corresponding outgoing lights, and are reflected by obstacles to form echo lights collected by different detectors. Therefore, the beam splitter prism realizes beam splitting through the principle of light refraction. Compared with the diffraction device, it reduces the dependence of the beam splitting angle on the wavelength of light, thereby being able to improve the beam splitting accuracy and controllability while increasing the number of laser lines without increasing the number of lasers, so as to improve the accuracy of the vertical angular resolution of the laser radar.

[0026] In an optional solution of the present invention, the beam splitter prism is arranged at the position of the aperture stop of the transmitting lens. In the laser radar optical system, the light spots of lasers at different heights on the focal plane at the position of the aperture stop are overlapped, so setting the beam splitter prism at the position of the aperture stop can split the light of multiple lasers in equal proportion, effectively reducing the difficulty of setting the beam splitter prism and facilitating improving the beam splitting accuracy.

[0027] In an optional solution of the present invention, the beam splitter prism includes one or more wedge prisms. The wedge prism itself is an optical device with a simple structure and convenient processing. The method of setting the beam splitter prism as one or more wedge prisms can effectively reduce the processing difficulty and assembly difficulty of the laser radar.

[0028] In an optional solution of the present invention, the vertical plane of the wedge angle edge line of the wedge prism is parallel to the meridian plane of the transmitting lens. The vertical plane of the wedge angle edge line of the wedge prism is set to be parallel to the meridian plane of the transmitting lens, so that the beam splitter prism can separate the detection light in the vertical direction, thereby increasing the vertical angular resolution of the laser radar without increasing the number of lasers.

[0029] In an optional solution of the present invention, the energy of the first emitted light, the second emitted light, the third emitted light, ..., and the X+1th emitted light is equal. By making the energy of each emitted light formed by a line of detection light equal, the maximum detectable distance of each emitted light can be ensured to be equal, thereby effectively ensuring the detection performance of the laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of a laser radar transmitter;

[0031] Figure 2 1 is a schematic diagram of the three-dimensional structure of an embodiment of a laser radar of the present invention;

[0032] Figure 3 yes Figure 2 A schematic diagram of the structure along the x direction in the laser radar embodiment shown;

[0033] Figure 4 yes Figure 2 A schematic diagram of the structure along the y direction in the laser radar embodiment shown;

[0034] Figure 5 yes Figure 2 A schematic diagram of the structure along the z direction in the laser radar embodiment shown;

[0035] Figure 6 yes Figure 2 Schematic diagram of the optical path structure of the laser radar aperture stop position shown;

[0036] Figure 7 yes Figure 2 A schematic diagram of a wedge-shaped prism and one half plane and ridge line thereof in the laser radar embodiment shown;

[0037] Figure 8 yes Figure 2 A schematic diagram of the optical path of outgoing light formed in the laser radar embodiment shown;

[0038] Fig. 9 yes Figure 2 A schematic diagram of the optical path of the outgoing light formed by the laser radar embodiment shown;

[0039] Fig.10 is a schematic diagram of the three-dimensional structure of another embodiment of the laser radar of the present invention;

[0040] Fig.11 yes Fig.10 A schematic diagram of the structure along the x direction in the laser radar embodiment shown;

[0041] Fig.12 yes Fig.10 A schematic diagram of the structure along the y direction in the laser radar embodiment shown;

[0042] Fig.13 yes Fig.10 A schematic diagram of the structure along the z direction in the laser radar embodiment shown;

[0043] Fig.14 yes Fig.10 A schematic diagram of the optical path of outgoing light formed in the laser radar embodiment shown;

[0044] Fig.15 yes Fig.10 A schematic diagram of the optical path of the outgoing light formed by the laser radar embodiment shown;

[0045] Fig.16 1 is a schematic diagram of the three-dimensional structure of another embodiment of the laser radar of the present invention;

[0046] Fig.17 yes Fig.16 A schematic diagram of the structure along the x direction in the laser radar embodiment shown;

[0047] Fig.18 yes Fig.16 A schematic diagram of the structure along the y direction in the laser radar embodiment shown;

[0048] Fig.19 yes Fig.16 A schematic diagram of the structure along the z direction in the laser radar embodiment shown;

[0049] Fig. 20 yes Fig.16 A schematic diagram of the optical path of a line of outgoing light formed by the laser radar embodiment shown;

[0050] Fig.21 1 is a schematic diagram of the three-dimensional structure of another embodiment of the laser radar of the present invention;

[0051] Fig. 22 is a schematic structural diagram of another embodiment of the laser radar of the present invention along the z direction;

[0052] Fig.23 It is a schematic structural diagram of another embodiment of the laser radar of the present invention along the z direction. DETAILED DESCRIPTION

[0053] As can be seen from the background technology, laser radars with spectrometers have problems with low spectroscopic accuracy and controllability. The following is an analysis of the reasons for the poor spectroscopic accuracy and controllability of a laser radar based on its structure:

[0054] refer to Figure 1 , showing a schematic structural diagram of a laser radar transmitting end.

[0055] The laser radar transmitting end includes: a light source 11, a transmitting lens 12 and a spectrometer 13 arranged in sequence along the optical path; the laser generated by the light source 11 is shaped (such as collimated) by the transmitting lens 12 to form a detection light; a line of detection light is split by the spectrometer 13 to form multiple lines of output light; generally speaking, the spectrometer 13 is a diffraction spectrometer, such as a grating, so as to achieve the purpose of converting a line of emitted laser into multiple lines (both one-dimensional and two-dimensional distributions are possible).

[0056] The diffraction spectrometer realizes spectrometry based on the diffraction principle. Its structure is at the micron level, which is equivalent to the wavelength of the detection light. Therefore, the spectroscopic angle of the diffraction spectrometer is sensitive to the wavelength of the detection light. The change of the detection light wavelength will cause the change of the diffraction angle, which will cause the change of the spectroscopic angle. For example, taking the laser radar with a 905nm laser as the light source as an example, the line width of the detection light generated by the laser is about 3nm, and the floating range of the laser center wavelength between batches is within ±10nm. On the other hand, the laser wavelength will change with the change of the equipment temperature. Still taking the laser radar with a 905nm laser as the light source as an example, the change rate of the laser wavelength with temperature is about 0.3nm / ℃. Considering that the operating temperature range of the laser radar is -20℃~+85℃, and combined with the difference in the center wavelength of the laser between different batches, the field of view angle and angular resolution of the output light of the laser radar using the diffraction spectrometer will change significantly at different ambient temperatures; the field of view angle and angular resolution of the laser radar of the same batch at the same ambient temperature will also change significantly.

[0057] For example, Figure 1 In the laser shown, the light source 11 is a laser that outputs 905nm light; the spectrometer 13 is a grating, such as a one-dimensional Dammann grating; the one-line laser output by the light source 11 forms five-line lasers after passing through the spectrometer 13. However, due to the influence of production batches, temperature, etc., the emission angles corresponding to the five-line lasers formed in different laser radars will have different offsets and fluctuations. In order to solve the technical problem, the present invention provides a laser radar, including:

[0058] A light source, wherein the light source is suitable for generating at least one line of detection light; a transmitting lens, wherein the transmitting lens is arranged downstream of the optical path of the detection light generated by the light source; a dichroic prism, wherein the dichroic prism is arranged on the optical path of the transmitting lens, and the dichroic prism covers a portion of the aperture stop of the transmitting lens; any detection light transmitted through the transmitting lens partially transmits through the dichroic prism, and partially does not transmit through the dichroic prism; the portion of the detection light transmitted through the dichroic prism and the portion of the detection light not transmitted through the dichroic prism respectively form corresponding emergent light, and the emergent light is reflected by an obstacle to form echo light collected by different detectors.

[0059] In the technical solution of the present invention, the splitting prism realizes splitting through the principle of light refraction. Compared with the diffraction device, the dependence of the splitting angle on the wavelength of light is reduced, so that the splitting accuracy and controllability can be improved while increasing the number of laser lines without increasing the number of lasers, so as to improve the accuracy of the vertical angular resolution of the laser radar.

[0060] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0061] refer to Figures 2 to 5 , shows a schematic structural diagram of an embodiment of a laser radar of the present invention.

[0062] in, Figure 2 shows a schematic diagram of the three-dimensional structure of the laser radar embodiment, Figure 3 yes Figure 2 A schematic diagram of the structure along the x direction in the laser radar embodiment shown; Figure 4 yes Figure 2 A schematic diagram of the structure along the y direction in the laser radar embodiment shown; Figure 5 yes Figure 2 A schematic diagram of the structure along the z direction in the laser radar embodiment shown.

[0063] The laser radar includes: a light source (not shown in the figure), which is suitable for generating at least one line of detection light; a transmitting lens 110, which is arranged downstream of the optical path of the detection light (not shown in the figure) generated by the light source; a dichroic prism 120, which is arranged on the optical path of the transmitting lens 110, and the dichroic prism 120 covers part of the aperture stop of the transmitting lens; any line of detection light transmitted through the transmitting lens 110 partially transmits through the dichroic prism 120, and partially does not transmit through the dichroic prism 120; the part of the detection light transmitted through the dichroic prism 120 and the part of the detection light not transmitted through the dichroic prism 120 respectively form corresponding output lights, and the output lights are reflected by obstacles to form echo lights collected by different detectors.

[0064] Any line of detection light that passes through the emitting lens 110 partially passes through the beam splitter prism 120, and partially does not pass through the beam splitter prism 120. Under the refraction of the beam splitter prism 120, the propagation direction of the part of the detection light that passes through the beam splitter prism 120 changes, thereby deviating from the original light path direction. Through the setting of the beam splitter prism 120, the part of the detection light that passes through the beam splitter prism 120 and the part of the detection light that does not pass through the beam splitter prism 120 respectively form corresponding outgoing lights, and are reflected by obstacles to form echo lights collected by different detectors. Therefore, the beam splitter prism 120 realizes beam splitting through the principle of light refraction. Compared with the diffraction device, the dependence of the beam splitting angle on the wavelength of light is reduced, so that the beam splitting accuracy and controllability can be improved while increasing the number of laser lines without increasing the number of lasers, so as to improve the accuracy of the vertical angular resolution of the laser radar.

[0065] The embodiments of the technical solution of the present invention are described in detail below with reference to the accompanying drawings.

[0066] The light source (not shown) is used to generate light.

[0067] In some embodiments of the present invention, the light source includes at least one laser. Each laser generates a line of detection light. Specifically, in this embodiment, the light source includes n lasers, so the light source generates n lines of detection light.

[0068] The emission lens 110 is disposed downstream of the detection light path and is suitable for shaping the light for emission.

[0069] In some embodiments of the present invention, the emitting lens 110 is suitable for collimating the detection light. Specifically, in this embodiment, the emitting lens 110 is a lens group composed of multiple lenses, which is used to collimate the detection light.

[0070] The beam splitter prism 120 is used to make any line of detection light form at least two lines of outgoing light in the vertical direction, which are then reflected by obstacles to form echo lights collected by different detectors.

[0071] The beam splitter prism 120 is disposed downstream of the optical path of the emitting lens 110, and the beam splitter prism 120 covers the aperture stop of the emitting lens 110, that is, the projection portion of the beam splitter prism 120 on the aperture stop of the emitting lens 110 is located within the range of the aperture stop.

[0072] Therefore, after any line of detection light passes through the emission lens 110, only a portion of it can be projected onto the beam splitter prism 120. Therefore, for any line of detection light, when passing through the beam splitter prism 120, only a portion of it passes through the beam splitter prism 120, and the portion that is not projected onto the beam splitter prism 120 does not pass through the beam splitter prism 120.

[0073] Part of the detection light that passes through the beam splitter prism 120 is refracted, and the optical path of this part of the detection light is changed, thereby forming an outgoing light whose propagation direction is different from that of the detection light; the part of the detection light that does not pass through the beam splitter prism 120 is not affected by any optical element, and the optical path is not changed, thereby forming an outgoing light whose propagation direction is the same as that of the detection light.

[0074] It can be seen that any one line of detection light forms at least two lines of outgoing light after the beam splitter prism 120. Specifically, in this embodiment, the n lines of detection light generated by the light source can form at least 2n lines of outgoing light for detection after passing through the beam splitter prism 120.

[0075] Therefore, the configuration of the beam splitter prism 120 can increase the number of outgoing light lines for detection without increasing the number of lasers, and can multiply the number of outgoing light lines without increasing the number of lasers, that is, improve the vertical angular resolution of the laser radar; and the beam splitter prism 120 realizes beam splitting by refraction. Compared with the diffraction device, the beam splitting angle is less dependent on the wavelength of light, which can greatly reduce the influence of the laser wavelength fluctuation on the field of view angle and angular resolution, and can effectively improve the beam splitting accuracy and controllability to improve the accuracy of the vertical angular resolution of the laser radar.

[0076] It should be noted that in the technical solution of the present invention, all the outgoing lights formed are used for detection, that is, the outgoing lights formed by all the detection lights are used for detection, that is, the light source includes m lasers, where m is an integer greater than or equal to 1, generating m-line detection lights; the m-line detection lights are transmitted through the transmitting lens and the beam splitter prism to form at least 2m-line outgoing lights, and the at least 2m-line outgoing lights are reflected by obstacles to form at least 2m-line echo lights; so the laser radar also includes: at least 2m detectors corresponding to the at least 2m-line echo lights one by one to collect the echo lights. Therefore, the laser radar includes more detectors than the number of lasers, and the number of detectors is greater than or equal to 2m.

[0077] In some embodiments of the present invention, the beam splitter prism 120 is disposed at the position of the aperture stop of the transmitting lens. The aperture stop is an inherent parameter of the transmitting lens (the transmitting lens may be a single lens or a lens group). Figure 6 As shown, in the optical system, when the laser is set on the focal plane 140, the light spots formed by the lasers at different positions are overlapped at the position of the aperture stop 130. Therefore, by setting the beam splitter prism 120 at the position of the aperture stop, multiple lasers can be split in equal proportion, which effectively reduces the difficulty of setting the beam splitter prism 120 and is conducive to improving the beam splitting accuracy.

[0078] In this embodiment, the beam splitter prism is located on the side of the emitting lens 120 away from the light source, that is, Figure 2 In the embodiment, the emitting lens 110 is located between the light source and the beam splitter prism 120. In other embodiments of the present invention, the beam splitter prism may also be located between the emitting lens and the light source or in the middle of the emitting lens.

[0079] In some embodiments of the present invention, the beam splitter prism 120 is fixed by bonding or a bracket. Specifically, in this embodiment, the beam splitter prism 120 is fixed to the optical system by a bracket (not shown in the figure).

[0080] In some embodiments of the present invention, the beam splitter prism 120 includes N wedge prisms, where N is an integer greater than or equal to 1. Figure 2 As shown, in this embodiment, the beam splitter prism 120 includes one wedge prism, that is, N is equal to 1. The wedge prism is an optical device with a simple structure and convenient processing. The method of using a wedge prism to construct the beam splitter prism has a simple optical path and a simple structure, which can effectively reduce the processing difficulty and assembly difficulty of the laser radar.

[0081] In some embodiments of the present invention, the angle between the vertical plane of the ridgeline of the wedge angle of the wedge prism 120 and the meridian plane 111 of the emitting lens 110 is not equal to 90°. It should be noted that the wedge angle in the wedge prism is a dihedral angle, wherein the two surfaces of the wedge prism are the half planes of the wedge angle, and the straight line where the two surfaces of the wedge prism intersect is the ridgeline of the wedge angle. Figure 7 Shows Figure 2 Schematic diagram of the wedge angle α of the wedge prism 120 and one half plane 121 and the ridge 122. Figure 2 The two surfaces intersecting each other (as shown in the figure) constitute a wedge angle α, the two surfaces constituting the wedge angle α and their extended planes are two half planes of the wedge angle α (one of the half planes 121 is shown in the figure), and the extended parts of the two surfaces constituting the wedge angle α intersect in a straight line, which is the ridgeline 122 of the wedge angle α, and the vertical plane perpendicular to the ridgeline 122 is a plane 123.

[0082] In addition, in this embodiment, the laser radar is a mechanical rotating laser radar, and the laser radar includes a rotation axis, wherein the rotation axis can be a through axis or a non-through axis. The plane including the optical axis and parallel to the rotation axis is the meridian plane 111 of the transmitting lens 110. Moreover, in this embodiment, the laser radar is a vehicle-mounted laser radar, that is, when the laser radar is in use, it is usually installed on the roof, around the vehicle, etc., and the rotation axis is in the direction pointing to the ground (that is, the vertical field of view direction, corresponding to the Y direction in the figure). Avoiding the vertical plane of the wedge angle edge line being perpendicular to the meridian plane 111 of the transmitting lens 110 can prevent the beam splitter prism 120 from separating the detection light only in the direction perpendicular to the meridian plane 111, that is, only in the horizontal field of view direction, the X direction in the figure, so that the beam splitting effect of the beam splitter prism 120 contributes in the vertical field of view direction to improve the vertical field of view angle and vertical angular resolution.

[0083] like Figure 2 As shown, in this embodiment, the vertical plane of the wedge angle ridgeline of the wedge prism 120 is parallel to the meridian plane 111 of the emitting lens 110, that is, the thickness of the wedge prism 120 gradually changes along the y direction. In this embodiment, the thickness of the wedge prism 120 gradually increases along the -y direction (from top to bottom); in other embodiments of the present invention, the thickness of the wedge prism 120 may also gradually increase along the y direction (from bottom to top).

[0084] By making the vertical plane of the wedge-shaped angle edge parallel to the meridian plane 111 of the emitting lens 110, the beam splitter prism 120 can separate the detection light only in the vertical field of view direction, thereby maximizing the use of the beam splitting angle of the beam splitter prism 120 and maximally improving the vertical field of view angle and vertical angular resolution without increasing the number of lasers.

[0085] It should be noted that, in this embodiment, the beam splitter prism 120 includes only one wedge-shaped prism, and the energy of the outgoing light formed by transmitting the wedge-shaped prism is equal to that of the outgoing light formed by not transmitting the wedge-shaped prism, so that the maximum detectable distance of all the outgoing lights formed by a line of detection light passing through the beam splitter prism 120 is equal. Therefore, at the position of the aperture stop, the radiation flux within the coverage of the projection of the wedge-shaped prism is equal to the radiation flux within the coverage of the projection of the wedge-shaped prism.

[0086] Combined with reference Figure 8 , showing Figure 2 A schematic diagram of the optical path of the outgoing light formed in the laser radar embodiment shown.

[0087] After being transmitted through the emission lens 110, the detection light propagates in a direction parallel to the z-axis (-z direction in the figure). When any line of detection light propagates to the position of the beam splitter prism 110, the propagation direction of the detection light not projected onto the beam splitter prism 110 remains unchanged, and the first emitted light 121 formed still maintains the propagation direction parallel to the z-axis.

[0088] The beam splitter prism 120 is a wedge-shaped prism with a refractive index of n and a wedge angle of α. Therefore, the detection light projected onto the beam splitter prism 120 is deflected by an angle of β in the y direction during transmission through the wedge-shaped prism, that is, the deflection angle between the second output light 122 and the first output light 121 is:

[0089] β=sin -1 (n·sinα)-α

[0090] It can be seen that by selecting a suitable wedge angle α and a wedge angle with a conversion rate n, the angular gap between the outgoing lights formed by a line of detection light can be adjusted, that is, the vertical angular resolution of the laser radar can be adjusted. Specifically, the deflection angle β can be made to be between the field of view angles of two adjacent lines of detection light, thereby playing a role in uniformly increasing the angular resolution.

[0091] like Fig. 9 As shown, it is shown Figure 2 Schematic diagram of the optical path structure of the outgoing light formed by the laser radar embodiment shown.

[0092] Specifically, the light source of the laser radar includes 8 lasers, which respectively form 8 lines of detection light. The spots of the 8 lines of detection light overlap on the aperture diaphragm of the transmitting lens; after the 8 lines of detection light are split by the beam splitter prism, they are divided into 16 lines of laser in the vertical field of view direction, where the dotted arrows represent the outgoing light 124 formed without being deflected by the beam splitter prism, and the dotted arrows represent the outgoing light 123 formed by being deflected by the beam splitter prism. The two outgoing lights with different propagation directions are intertwined in the vertical field of view direction (y-axis direction). It can be clearly seen from the figure that the vertical angular resolution is significantly improved due to the setting of the beam splitter prism.

[0093] It should be noted that in some embodiments of the present invention, the material of the beam splitter prism is optical glass, preferably low-dispersion glass, which generally refers to glass with an Abbe number greater than 80. The use of a beam splitter prism made of low-dispersion glass can further reduce the influence of wavelength on the beam splitting angle, effectively improve the control accuracy of the beam splitting angle, and thus improve the accuracy of the vertical angular resolution of the laser radar.

[0094] refer to Figures 10 to 13 , shows a schematic structural diagram of another embodiment of the laser radar of the present invention.

[0095] in, Fig.10 shows a schematic diagram of the three-dimensional structure of the laser radar embodiment, Fig.11 yes Fig.10 A schematic diagram of the structure along the x direction in the laser radar embodiment shown; Fig.12 yes Fig.10 A schematic diagram of the structure along the y direction in the laser radar embodiment shown; Fig.13 yes Fig.10 A schematic diagram of the structure along the z direction in the laser radar embodiment shown.

[0096] The present invention will not repeat the same points as the previous embodiment. The difference from the previous embodiment is that in this embodiment, the vertical plane of the wedge-shaped angle edge of the beam splitter prism 220 intersects with the meridian plane of the emission lens 210.

[0097] Combined with reference Fig.14 , when the angle between the vertical plane of the wedge angle edge of the wedge prism and the meridian plane is (90°-θ) (such as Fig.13 When any line of detection light is transmitted through the wedge-shaped prism, it is deflected by an angle β in the x direction and by an angle γ in the y direction, that is, the angle between the projection of the outgoing light transmitted through the beam splitter prism 220 in the xz plane and the outgoing light not transmitted through the beam splitter prism 220 is β, and the angle between the projection of the outgoing light transmitted through the beam splitter prism 220 in the yz plane and the outgoing light not transmitted through the beam splitter prism 220 is γ. The deflection angles β and γ are respectively:

[0098] β=tan -1 (tan(sin -1 (n·sinα)-α)×cos(θ))

[0099] γ=tan -1 (tan(sin -1 (n·sinα)-α)×sin(θ))

[0100] It can be seen that by selecting a suitable wedge angle α and a wedge angle with a conversion rate n and setting the position of the wedge prism (i.e. setting the angle between the vertical plane of the wedge angle edge line of the wedge prism and the meridian plane to (90°-θ)), the gap between the outgoing light formed by a line of detection light in the vertical and horizontal directions can be controlled, and the angular resolution of the multi-line outgoing light formed by a line of detection light in the vertical and horizontal directions can be adjusted.

[0101] Combined with reference Fig.15 , showing Fig.10 A schematic diagram of the outgoing light formed by the laser radar embodiment shown.

[0102] The laser radar light source includes 8 lasers, which generate 8 lines of detection light; the beam splitter includes a wedge prism with a wedge angle of 5°, the material of the wedge prism is N-BK7 glass, and the angle between the vertical plane of the wedge angle edge and the meridian plane is 67.3°, that is, the wedge prism rotates 22.7° around the z-axis. After passing through the beam splitter, the 8 lines of detection light generated by the light source form 16 lines of outgoing light separated in the vertical direction and the horizontal direction.

[0103] refer to Figures 16 to 19 , shows a schematic structural diagram of another embodiment of the laser radar of the present invention.

[0104] in, Fig.16 shows a schematic diagram of the three-dimensional structure of the laser radar embodiment, Fig.17 yes Fig.16 A schematic diagram of the structure along the x direction in the laser radar embodiment shown; Fig.18 yes Fig.16 A schematic diagram of the structure along the y direction in the laser radar embodiment shown; Fig.19 yes Fig.16 A schematic diagram of the structure along the z direction in the laser radar embodiment shown.

[0105] The present invention will not repeat the same points as the above-mentioned embodiments. The difference from the above-mentioned embodiments is that in the present embodiment, the beam splitter prism 320 includes N wedge prisms, where N is greater than 1.

[0106] In some embodiments of the present invention, when N is greater than 1, the N wedge-shaped prisms are sequentially stacked along the optical path. As shown in the figure, in this embodiment, the beam splitter prism 320 includes two wedge-shaped prisms, which are sequentially stacked along the optical path, namely, the first wedge-shaped prism 321 and the second wedge-shaped prism 322. Therefore, after the detection light passes through the emission lens 320, part of it only passes through the first wedge-shaped prism 321, and part of it passes through the first wedge-shaped prism and the second wedge-shaped prism 322 in sequence.

[0107] In some embodiments of the present invention, the range of the aperture stop covered by the Mth wedge-shaped prism is within the range of the aperture stop covered by the M-1th wedge-shaped prism, where M is an integer in the range of 2 to N. As shown in the figure, in this embodiment, the range of the aperture stop covered by the second wedge-shaped prism 322 is within the range of the aperture stop covered by the first wedge-shaped prism 321. Therefore, after passing through the first wedge-shaped prism 321, part of the detection light is projected onto the second wedge-shaped prism 322.

[0108] It should be noted that, in this embodiment, among the N wedge-shaped prisms of the beam splitter prism 320, along the direction from the light source to the emission lens 310, the range of the aperture stop covered by the N wedge-shaped prisms becomes smaller and smaller. Therefore, the M-1th wedge-shaped prism is located between the Mth wedge-shaped prism and the light source. In other embodiments of the present invention, along the direction from the light source to the emission lens 310, the range of the aperture stop covered by the N wedge-shaped prisms becomes larger and larger, then the M-1th wedge-shaped prism is located on the side of the Mth wedge-shaped prism away from the light source, that is, the Mth wedge-shaped prism is located between the M-1th wedge-shaped prism and the light source.

[0109] In addition, as shown in the figure, in this embodiment, the vertical planes of the wedge angle edges of the N wedge angle prisms are parallel to each other, that is, the vertical planes of the wedge angle edges of the N wedge angle prisms are equal to the angle between the meridian plane of the emitting lens 310, so as to reduce the complexity of the laser radar optical path and effectively reduce the difficulty of assembly.

[0110] In some embodiments of the present invention, part of the detection light that has not passed through the wedge-shaped prism forms the first output light; part of the detection light that has passed through one wedge-shaped prism forms the second output light; part of the detection light that has passed through two wedge-shaped prisms forms the third output light; ...; part of the detection light that has passed through X wedge-shaped prisms forms the X+1th output light, where X is an integer in the range of 1 to N.

[0111] Specifically, in this embodiment, the portion of the detection light that has not passed through the first wedge-shaped prism and the second wedge-shaped prism forms the first outgoing light, the portion of the detection light that has passed through the first wedge-shaped prism forms the second outgoing light, and the portion of the detection light that has passed through the first wedge-shaped prism and the second wedge-shaped prism forms the third outgoing light (as shown in FIG. Fig. 20 shown).

[0112] It should be noted that the energies of the first outgoing light, the second outgoing light, the third outgoing light, ..., and the X+1th outgoing light are equal, thereby ensuring that the maximum detectable distance of each outgoing light formed by a line of detection light is equal, thereby effectively ensuring the detection consistency between the corresponding channels of the laser radar.

[0113] In some embodiments of the present invention, the light source includes Z lasers to generate Z-line detection light; part of the detection light is transmitted through at most X wedge-shaped prisms; the laser radar also includes: a detector, which is suitable for receiving the echo light; the number of the detectors is Z×(X+1).

[0114] Since all the outgoing lights are used for detection, that is, the Z-line detection light generated by the light source forms Z×(X+1) outgoing lights after transmitting through the X wedge-shaped lenses of the spectroscopic lens; in order to achieve one-to-one detection of all the outgoing lights, the number of detectors in the laser radar is equal to the number of the outgoing light rays.

[0115] Specifically, in this embodiment, the laser radar light source includes 8 lasers, generating 8 lines of detection light; the beam splitter prism 320 includes 2 wedge prisms, namely the first wedge prism 321 and the second wedge prism 322. Therefore, the beam splitter prism 320 can separate the 1(n) line of detection light in the vertical direction into 3(3n) lines of outgoing light in the vertical direction. (As shown in FIG. Fig. 20 As shown). Therefore, the 8-line detection light generated by the light source eventually forms 24-line output light for detection, thereby doubling the number of laser lines used for detection without increasing the number of lasers, which can not only control the cost of the laser, but also reduce the cost of the driving current, and also improve the reliability of the laser radar.

[0116] In addition, if Fig.16 As shown, in this embodiment, the vertical plane of the wedge angle ridgeline of the N wedge prisms is parallel to the meridian plane. However, this arrangement is only an example, and in other embodiments of the present invention, the vertical plane of the wedge angle ridgeline of the N wedge prisms may also intersect with the meridian plane.

[0117] like Fig.21 As shown, it is a schematic diagram of the three-dimensional structure of another embodiment of the present invention. Fig.21 In the illustrated embodiment, the beam splitter prism 320 includes two wedge-shaped prisms, which are stacked in sequence along the optical path, namely, the first wedge-shaped prism 323 and the second wedge-shaped prism 324. Therefore, after the detection light is transmitted through the emission lens 310, part of it is transmitted only through the first wedge-shaped prism, and part of it is transmitted through the first wedge-shaped prism and the second wedge-shaped prism in sequence. The vertical plane of the wedge angle ridgeline of the first wedge-shaped prism 323 and the second wedge-shaped prism 324 intersects with the meridian plane, that is, the two wedge-shaped prisms in the beam splitter prism 320 are rotated by a certain angle around the z-axis (that is, the z-axis is parallel to the optical axis).

[0118] Reference 22 shows a schematic diagram of the structure of another embodiment of the laser radar embodiment of the present invention.

[0119] in, Fig. 22 is with Fig.19 The corresponding structural schematic diagram along the z direction.

[0120] The difference between this embodiment and the previous embodiment is that, in some embodiments of the present invention, the beam splitter prism includes two wedge prisms, namely the first wedge prism 421 and the second wedge prism 422, and the range of the aperture stop covered by the first wedge prism 421 and the second wedge prism 422 partially overlaps. In addition, the beam splitter prism only covers a part of the range of the aperture stop, that is, part of the aperture stop is not covered by the beam splitter prism (such as Fig. 22 as shown in the middle area 410).

[0121] In this embodiment, the wedge angles of the first wedge prism and the second wedge prism are not equal, so the included angle between the outgoing light formed by only transmitting the first wedge prism 421 and the outgoing light that has not transmitted the beam splitter prism is not equal to the included angle between the outgoing light formed by only transmitting the second wedge prism 421 and the outgoing light that has not transmitted the beam splitter prism. Therefore, although the beam splitter prism only includes two wedge prisms, any one line of detection light can form four lines of outgoing light after transmitting the beam splitter prism.

[0122] Specifically, part of the detection light that does not pass through the wedge-shaped prism forms the first output light, part of the detection light that only passes through the first wedge-shaped prism forms the second output light, part of the detection light that only passes through the second wedge-shaped prism forms the third output light, and part of the detection light that passes through the overlapping part of the first wedge-shaped prism and the second wedge forms the fourth output light. The energies of the first output light, the second output light, the third output light and the fourth output light are equal to ensure that the detection distances of the first output light, the second output light, the third output light and the fourth output light are equal.

[0123] It should be noted that, in this embodiment, the beam splitter prism only includes the first wedge prism and the second wedge prism, two wedge prisms. However, this is only an example. In other embodiments of the present invention, the number of wedge prisms in the beam splitter prism can also be more to split any line of detection light into more outgoing light, further improving the angular resolution. Fig.23 In the laser radar embodiment shown in FIG. 1 , the beam splitter prism includes five wedge prisms, namely a first wedge prism 521, a second wedge prism 522, a third wedge prism 523, a fourth wedge prism 524, and a fifth wedge prism 525. In addition, the beam splitter prism only covers a portion of the aperture stop, that is, part of the aperture stop is not covered by the beam splitter prism (e.g., Fig.23 (shown in area 510)

[0124] It should also be noted that, in this embodiment, the edges of the first wedge-shaped prism and the second wedge-shaped prism are parallel. However, this is only an example. In other embodiments of the present invention, the edges of the multiple wedge-shaped prisms in the beam splitter prism may also intersect. Fig.23 In the laser radar embodiment shown, the edges of the five wedge-shaped prisms in the beam splitter prism intersect.

[0125] In summary, in a mechanical rotating laser radar without the dichroic prism, the number of laser lines used for detection in the vertical field of view direction is equal to the number of lasers included in the light source. However, in the technical solution of the present invention, the dichroic prism is provided in the optical path of the laser radar. The dichroic prism can divide a line of detection light generated by any laser in the light source into multiple lines of outgoing light for detection. Moreover, by setting the structure and position of the dichroic prism, the outgoing light formed can be separated in the vertical field of view direction, or the vertical field of view direction and the horizontal field of view direction, and the corresponding number of detectors are set to collect the outgoing light one by one. Therefore, the number of outgoing light rays used for detection can be increased without increasing the number of lasers, so as to improve the scanning field of view angle and scanning angle resolution; in addition, the dichroic prism realizes dichroism through the principle of refraction. Compared with the diffraction device, the dichroic angle has little dependence on the wavelength of light, which can greatly reduce the influence of the light wavelength fluctuation on the dichroic angle, which is beneficial to the improvement of the vertical angular resolution accuracy of the laser radar.

[0126] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A laser radar, characterized in that: include: a light source adapted to generate at least one line of detection light; An emitting lens, the emitting lens being arranged downstream of the optical path of the detection light generated by the light source; A beam splitter prism, the beam splitter prism is arranged on the optical path of the emitting lens, and the beam splitter prism covers a portion of the aperture stop of the emitting lens; Any line detection light transmitted through the emission lens partially transmits through the beam splitter prism, and partially does not transmit through the beam splitter prism; The part of the detection light that transmits the beam splitter prism and the part of the detection light that does not transmit the beam splitter prism form corresponding outgoing lights respectively, and the outgoing lights are reflected by obstacles to form echo lights collected by different detectors.

2. The laser radar according to claim 1, characterized in that The dichroic prism is arranged at the position of the aperture stop of the emitting lens.

3. The laser radar according to claim 2, characterized in that The beam splitter prism is located between the emitting lens and the light source, or on a side of the emitting lens away from the light source, or in the middle of the emitting lens.

4. The laser radar according to claim 2, characterized in that The beam splitter prism is fixed by bonding or by a bracket.

5. The laser radar according to claim 1, characterized in that: The beam splitter prism includes N wedge prisms, wherein N is an integer greater than or equal to 1.

6. The laser radar according to claim 5, characterized in that The included angle between the vertical plane of the wedge angle edge line of the wedge prism and the meridian plane of the emitting lens is not equal to 90°.

7. The laser radar according to claim 5 or 6, characterized in that: The vertical plane of the wedge angle edge line of the wedge prism is parallel to the meridian plane of the emitting lens.

8. The laser radar according to claim 5, characterized in that When N is greater than 1, the N wedge-shaped prisms are stacked in sequence along the optical path.

9. The laser radar according to claim 8, characterized in that: The vertical planes of the wedge angle ridges of the N wedge prisms are parallel.

10. The laser radar according to claim 8, characterized in that: The range of the aperture stop covered by the Mth wedge-shaped prism is within the range of the aperture stop covered by the M-1th wedge-shaped prism, where M is an integer in the range of 2 to N.

11. The laser radar according to claim 10, characterized in that: The part of the detection light that has not passed through the wedge-shaped prism forms the first output light; The portion of the detection light transmitted through X wedge-shaped prisms forms the X+1th emergent light, where X is an integer in the range of 1 to N.

12. The laser radar according to claim 11, characterized in that: The energies of the first emitted light, the second emitted light, the third emitted light, ..., and the X+1th emitted light are equal.

13. The laser radar according to claim 11, characterized in that: The light source includes Z lasers to generate Z-line detection light; Part of the detection light is transmitted through at most X wedge-shaped prisms; The laser radar further comprises: a detector, which is suitable for receiving the echo light; The number of detectors is indivual.

14. The laser radar according to claim 1 or 11, characterized in that: The number of detectors is equal to the number of outgoing light lines.

15. The laser radar according to claim 8, characterized in that: The beam splitter prism includes two wedge-shaped prisms, namely a first wedge-shaped prism and a second wedge-shaped prism. The wedge angles of the first wedge-shaped prism and the second wedge-shaped prism are not equal, and the ranges of the aperture stop covered by the first wedge-shaped prism and the second wedge-shaped prism partially overlap.

16. The laser radar according to claim 15, characterized in that: The portion of the detection light that has not passed through the wedge-shaped prism forms the first output light, the portion of the detection light that has only passed through the first wedge-shaped prism forms the second output light, the portion of the detection light that has only passed through the second wedge-shaped prism forms the third output light, and the portion of the detection light that has passed through the overlapping portion of the first wedge-shaped prism and the second wedge-shaped prism forms the fourth output light. The energies of the first output light, the second output light, the third output light and the fourth output light are equal.

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